Engine starter



Sept. 14, 1943. J. w. FlTZ GERALD ENGINE STARTER Filed Aug. 1. 1941Patented Sept; 14 1943 l I 1 Panama STARTER John FitzGeraId, Milwaukee,Wis, assignor to Q I Briggs & S'tratton Corporation, Mjlvvaukee, v

' TW is; a corporation of Delaware" Application ugust}, 1941; SerialNGAOEJHQ 21 Claims; (o1.74-'7) This invention relates to enginestarters,and

I refers particularly to the so -called automatic type of starterwherein inertia is-relied upon to effect relative rota't ionfbetween astarter gear or pinion and its power driven actuator top'ropel thepinion to and from"operative drivingt'ei igagement a -i U,

Due to the' adventflof 'o'il'clutches inarito'mo biles, the use of theseautomatic starters has en-o iwit h' the flywheel ofyan engine to becountered a serious problem. As, will be readily V under low'temperature conditionsj Under these condil aions the' oil filinfrictionfreezes the pinion to the starter shaft Inertia, therefore, is notenough to assure the necessary relative motion between the, coactingzscrew th11eaded3parts and as a consequence I the piniorr instead-cf-moving:

orwardlyntolmesh,withathe r n g l -takencthrough Figure "It on the.planewcf-theline directed was provision of simple but.effective'smeansforeverrevolveswithiits actuator; '5

"This invention is; therefore,

the ring "gear;

'=Ano'the'r o'b'ect' or this iii-ventio'n js the 1pmvision of"centritugally 'respon'sivemeans .fcr retardin'g the-retraction v -ofthe pinion to prevent objectional rebound.

Still another object of *thi'sfinve'n on A topro vide a singlecentrifugally-responsive means for advancing the iiinion andalso-retarding its Iretraction. o Withv'theabov'e an'do'ther; objects inview which will appear 7 as the description 'proceeds, this" inventionresides jin'th'e novel rcons'truction, commade ascomefiwithin'.the:scopefof the iclai'ms.

coming this objectionable possibilityand insur ing translation bf"the-Dinion.;irito'- m'esh' withthe ring' g'ea'r eventhou hthe crewthreadediparts ma be Is'tuck together ty 'a; e agealea 'oil film.

, With avi'w'toward stIUcturaFsimplicity;it is a furtherobject of this-invention to utilize centrifugal force to 'eifect thefnecessarv"relative rotation {between the: starter ea Il actuator.

Lenqf 'e t a offth inveht niisto rovide; means for augmenting inertiafin eiiectin'g'i rela? tive rotation between thefistarter "gear and "itse tuato giiwhic depe d's' m- I off the' autoniobileo'r'itslenginejandwhich is entirely self ccnt'ained within starter mec'ha- Hism ",Mbrespecifically; object of this inven-ithin to provide'fastarterfhaving "acentrifugally m i i h e 1 1 98?m llei qn qma ried b yt the-powerdriven-actuatorto turn thereno other function;

with and connectedf-to "the starter gear-in such m hner hat ts esm,.0:-. 2 I i a Q-ieb the ta;rter.1 e cetw h re ect. to; its.

bination' and arrangement of parts' substaintially as hereinafter,ilescribed' 'and' rnore particularly I defined b'ythe appendedclaimsgitbeing under I stood that such changes in the "-pre'ciseernbodi- I mentof the; hereindisclosed? invention may be The accompanyingidrawin'gi1l'ustrates"one coin plete example of the physical embodiment of theinvention constructed acccrdingl'to the best mode so far devised for theractical"application of the-principles thereof, andin which:

Figurel is a view partly in sideelevationg and partlyin'lon'gitudinalsection of an engine starter embodyingthis invention'; A

-1FigUIe 2 is an enlarged cross (sectional view,

Figure 4-is' 'a-perspective vi'ewfcf ,;;the entire I starter.- 1

parts, the numeral '5 designates a power driven driveshaftwl'iich'ispreferablythe armatureshait tion with the 'shacft'i provided.bya rubberrring- I2 Confined between f iangesrl3andrldmThelfon tarter-With I i I 1 Referring now particularly to,- the a ccoinpany in'gdrawingin whichli ke numerals designate like mer of these flanges is fixed tothe screw threaded actuating member H and the latter has a hub l5 bywhich it is fixed to the drive shaft 5.- A cup-shaped outer shell I6having its open end secured-to the flange l4 encloses both flanges andthe rubber ring and by a medial shoulder limits motion of the flange l3away from the flange 14. The rubber ring is thus held under pressurebetween-the flanges to provide initial frictional driving engagement totransmit torque I resiliently from the shaft to the screw threadedactuating member. I I.

Hence, when the drive shaft begins to revolve,

the inertia of the starter gearand its sleeve holds the same stationarywhile the actuator l l revolves and demesh type. the, combination with:a power driven member; and amember connected with the starter gear andthreaded to saidpower driven member so that relativerotation betweentherein to propel the'pinion' forwardly into mesh' v with the ring gear.Forward propulsion of the pinion is. limited by the engagementof a stopflange IT on the pinion extension with the end of the shell l6 which isflanged inwardly.

Under normalconditions, inertiamay berelied upon to effect the necessaryrelative rotation between the -pinion and its actuator but if thestarter must ,operatein conditions where it is subjected to excessiveoil as. in engines. equipped with oil clutches, the required freerunning fit between the pinion sleeve and. actuator cannot be maintainedespecially in cold weather.

Under/such conditions, the oil film which is excessive congeals and mustbe broken to insure advance ofthe pinion into mesh with the ring gear..To this end, the front end l6 of the shell has a weightedcentrifugallyresponsive leverl8 pivoted thereto as at IS. The outerWeighted end of this lever is coupled to one endof a brake band saidmembers effects translation of the starter gear into. and out of meshwith the ring gear of the engine to be started; of a centrifugallyresponsive device; and means actuated bythe centrifugally responsivedevice in consequence to its responseto centrifugal force forefiectingthe necessary relative rotation between said members to advance thestarter gear toward the engine ring gear.-

-.2..In an engine"; starter of theautomatic mesh and demesh type havinga powerdriven member and-a startergear'memberscrew threaded tolflsaidpcwer'drivenmember; means for augmenting inertia normally relied upon,for effecting relativerotation' between said members as the starterbegins to operate to insure advance of the starter gear, said meanscomprising a centrifugally respons'ive member revoluble with the powerdriven member and adapted to swing out from a normal" position inresponseto centrifugal force and, a.,driving connectionibetween saidcentrifugally responsive member and the starter 20 preferably by meansof a. chain link 2,! engaging in a loop on the lever.

I The opposite end of the brake band "is connected to a'fixedanchor'as'for instance the pivot l9 by means of a tension spring 22.Hence; when the "starter is stationary these parts assumethesameQthispull on the band rotates the pinion with relatio-nto itsactuatorv l Lg. The direction ofrotationisindicated'by the arrow:23, andis such that forward translation of the pinion takes Place; q 7

After the engine starts and the pinion-over runs the actuator, it' isretracted' in the normal manner but by virtue of the engagement of thebrake band with thepinion' sleeve the retraction centrifugal. forceceases to hold the weighted lever out and the spring 22 restores theparts to their normal positions, a turning moment is i1n-- parted tothepinion in the" direction necessary to retract the same. 1 w a j Hence,the means; here provided for augmenting inertia to insure meshing ofthe'start'er pinion with the ring gear also has an anti-bounce functionwhich is highly desirable. 7

Inasmuch as the brake band is constantly maintained'under tensionby thespring 22and is wrapped about the pinion sleeve at'all times, it

follows that an anti-creep function is inherent in the'str'uctu're ofthis invention.

Thisinvention' also makes possible a very degear member for. turning.the starter gear memher with relation to the-power driven member in gthe directionnecessaryto propel thestarter gear forwardly. p

3. In 'an engine starter, the combination with: a starter gear and powerdriven means having a part thereofprovided with a screw threadedconnection with the starter gear; 'centrifugally responsive meansrotatable withthe power driven means and having a motion transmittingconnection with the starter gear rendered effective upon response ofsaid means'to centrifugal force, said centrifugally-F-responsive meansacting on' the starter 'gear upon initial operationof the starter toaugment inertia normall'yrelied uponto effect relative rotation betweenthe starter gear and said .parto'f the power driven means'and beingoperable to effect the, relative rotation between the starter gear'andpower driven part necessary to effect propulsion ,of' the starter geartoward l of the pinion is materially slackened. In other- I words; thebrake band" imposes a drag; "on the pinion to reduce 'the speedolfitsrotation. This effectively prevents rebound. :Moreover, when operativeposition-asthestarter begins to operate.

4;;In an engine, starter: astarter gear movable to. and from meshwiththe rinlggear of an engine to be started; a powerdriven a actuatorfor the starter gear; a screw threaded connection be-v tween theactuator and the starter gear sothat relative rotation between saidparts in one direction propels. the pinion forwardly into mesh with theringgear; a Jweighted member pivotally mounted to revolve'with the powerdriven actuator, and to swing" out on its pivotal mounting in response,to centrifug'alforce;v and'means connecting said pivotal 'member with'the starter gear and utilizing the outward swinging motion .of saidmember to effect relative rotation between thegear andits actuator in,the direction necessary to propel the pinion forwardly.

5. 'In 'anTengine'starter; a starter gear movable to and from mesh-withthe ring gear ofan engine tobe startedya power driven actuator for thestarter gear; a screw threaded connection between the actuator-and thestarter gear sothat 2;s 2e,: i-74 I starterigear withaelation to 'theactuator' in rerelative rotation between said parts inonedirectionipro'pelsitheipinion forwardly into mesh with 'the :ring gear;a weighted :mem'ber 'pivotally mounted to revolve with the powerdrivemactuator andft'olswingout on its .'pivotalmounting inresponseztocentrifugal force; and a member connected with said pivotedweighted member and :friCtiOriallyengaging a part ofthe starter gear.to'turn :the same with relation to its actuator as I :theweightedmember swings out in response to centrifugal force. W r.

'6." In an engine starter: a starter gear movable to :and'from mesh withthe ring gear-of an engine to. be started; a, power driven actuator forthe starter gear; a screw threaded connection'between the actuatorand'the starter gearso that relative rotation between said parts in one'direction pro i :pels :theipinion-forwardly into mesh with the ringgearyajweighted member pivotally mounted 't'o starter gear; a screwthreaded connection between theiractuator iand the starter gear so thatrelative rotation between said parts in one direction propels the pinionforwardly into mesh'with the ring gear; a weighted member p'ivotallymountedtorevolve with the .power drivenactw ator and to swing outonitslpivotal"mounting: in response vto centrifugal force; 'aimemberpartially wrapped about a part ton/the. starterigearand connected withsaid weighted member, said wrapped member having frictional engagementwith said part on the'starter gear-so as to turn the same with relationto its actuator as the weighted member swings out in response tocentrifugal' force; and spring means for returning said wrapped memberand the weighted member to their normal positions. I v

8. In an engine starter: a starter gear having an internally threadedcylindrical extension; a

spouse :to outward mo'tion'of the weighted ilever byrcentrifiigal'frorcer and ra fspring connected with 'saidcbrakelbandlforcreturninglitiandithe'wei'ghted 10. In an engine starterz, a.startrifgear mountedifo'r 'translationito 'and from an operativedriving-position; ia cylindrical extension on the starter gear; a power:tiriven' actuator fhaving 'a screw threadedconnection-with saidstarterigear so :that relative :rotation between :the :actuator andthestarter-. geartranslates the 'start'er 'igear to" and:fromroperat'iveapositionpabrake band partiallyiwrapped iabout thecylindrical :extensionof the; gear; :a' s'yielding support for I one endof *the brake'bandtzand:azweighted 'centrifu'gally respon sive:membe'rmounted to revolve-with the 'power drivenkactuatormnd' eonnected:with the l opposite end of Ft'h'e I brake irba'nd v to exert a pullther e'en as the weighted "centrifugall-y responsive member responds-itoicentrifugal iforc'e to thereby effect to and from mesh with the'ringg'ear of 'anengine to be started; a powerldriven actuator for thelingm'ember. t 12. .Intranengine relative rotation between the starter gearand its actuator in a' direction necessary to propel thestarter;gear'.:forwardly toward operative position.

, rllzrrIn an 'eng ine 'starterz' power' drivenin'eans including an:actuating member fa' starter :gear connected 'with'the actuating memberso ias to beimoved into engagement with :a member: of fan engine "to*be': started in iconsequence to relaitive rotation between the startergea'r and actuating membem 'and fcentrifugally responsive me'ans' energiz'ed-by rot'ation iof the aotuating n'iember and connected withthestarter gear.-'so rthat'response of said means to centrifugaliforcee'flects irelative rotation ibetweeniithe is'tarterigear and the actuat-SItar'terE I a motor driven starterbshaft; aLpinion movable along theshaft into engagementFWith a memberof an engine'to bevstarted; a drivingconnection 'between the pinion" and said. shaftfioperable, to propel ther pinion alongithe sharit -into mesh with the' 'ri ng gear of an engineto, be started upon relative power driven actuator screw threaded intosaid extension and operable upon relative rotation between it and saidcylindrical extension to propel the starter gear forwardly; a partrevoluble with the actuator'and havinga portion thereof adjacent to thecylindrical extension of the starter gear; a weighted lever pivoted tosaid part; and

a brake band partially wrapped about the cylindrical extension of thestarter gear and con-.

nected with said weighted lever to turn the starter gear with relationto the actuator in response I to outward motion of the weighted leverbycentrifugal force. s

9. .In an engine starter: a starter gear having an internally threadedcylindrical extension; a power driven actuator screw threaded into saidextension and operable upon relative rotation between it and saidcylindrical extension to propel the starter gear forwardly; a partrevoluble with the actuator and having a portion thereof adjacent to thecylindrical extension of the starter gear; a weighted lever pivoted tosaid part; a brake band partially wrapped about the cylindricalextension of the starter gear and connected with said weighted lever toturn the rotation between the pinion andthe starter shaft; andcentrifugally responsive means having a motion transmitting connectionwith the pinion operable upon response of said means to centrifugalforce-to insure relative rotation between the pinion andthe startershaft. I

13. In an engine starter: a pinion movable longitudinally toand from anoperative driving position; power driven means including anactuatingmember; a screw threaded connection between the actuatingmember and the pinion whereby relative rotation between said partseffects longitudinal movement of the pinion; and centrifugallyresponsive means revoluble with the power driven means and operable onthe pinion to effect relative rotation between said parts in a directionto advance the pinion.

14. In an engine starter: power driven means including an actuatingmember; a starter gear member; a threaded connection between saidmembers whereby relative rotation therebetween efiect's translation ofthe starter gear member from and to a retracted position; andcentrifugally' responsive means .carried by said powerv driven means and"acting on the starter gear member throughout substantially its entireretraction to retard such retraction and thus prevent rebound of thestarter gear member from its retracted position.

able endwise therebyl toiand from an operative drivingposition engagingamember'of an engine to be started; andasingle centrifugally responsivemeans operable-to efiectendwise motion of the starter gear toward itsoperative driving position and to retard retraction of the gear toprevent rebound. v I 1 4 a t 16. In an engine starter: a power drivenmember; 'a'pinion; a threaded connection between the pinion and saidpower driven member whereby relative rotation betweensaidparts effectstranslation of thepinion to and from an operative driving position; acentrifugallyresponsive member revolublewith the actuating member; andmeans connecting said 'centrifugally responsive member with the pinion.whereby'response of said centrifugally responsive member revolves thepinion with relation to the=actuating member to propelthegpinion towardoperative position and 4 whereby retraction of the pinion is retarded. i

s 17. In anengine starter; power driven means including anactuating.member;.a pinion'having a threaded sleeve; a threadedconnection between the pinion sleeve vand said actuating member wherebyrelative rotation between said parts effects translation .-of the-piniontoy and from an operative driving positionya centrifugally re sponsivemember revoluble with the. power driven means; and a brake bandconnected with the centrifugally responsive member and wrapped about thepinion'sleeve whereby the pinion sleeve is revolved relativeto theactuating member durin operation of the starter'to propelthe pinion'pinion sleeve.

carried by said power driven meansand operable on the pinion member toretard translation of said pinion member from operative position toretracted position.

, 1 9. In an engine starter: a power driven member; a pinion; having athreaded sleeve;. a threaded connection between the pinion sleeve andsaid power driven member whereby relative rotation between said partseffects translation of the pinion to and from any operative drivingposition; a brake band wrapped about thepinion sleeve; and meansconnected with the power driven member and maintaining the brake band intension and frictionally engaged with said 20.'In an engine starter: apower driven'member; a pinion; a cylindrical member fixed with betweenthe pinion and the power driven member whereby relative rotation betweensaid parts effects translation of the pinion to and from an operativedriving position; a centrifugally responsive member revoluble with thepower driven member; a brake band having one end connected with thecentrifugally responsive member and wrapped about the cylindricalmember; and means connected'with'theoppositeend of the brake band formaintaining the brake band in tension and frictionally engaged with saidcylindrical member. I

21. In an engine starter of the type wherein a pinion is automaticallypropelled to and from an operative driving position by relative rotationbetween a nut and screw: 2, power driven shaft on which the starter ismounted; centrifugally responsive means at all times rotatable with theshaft; and meansactuated by the centrifugally responsive means andoperable to effect relative rotation; and centrifugally responsive"means rotation between the nut and screw in the direc- JOHN W. FITZGERALD

